How many planets does it take to make the world go round? Put this question to your students - or colleagues - and the response is likely to be baffled looks. But if everyone used the Earth's resources at the same rate as people in Britain and the US, we would need not one planet to live on, but three.
This rate of consumption, according to wildlife charity WWF, means that we are spoiling some of the world's richest forests, are close to overfishing many of our seas and driving some species perilously close to extinction. Many climate scientists agree that if we continue to live in this way, and allow global temperatures to rise by more than 2 degsC, the damage to the Earth's fragile ecosystems may be irreversible.
But how can we convey these facts to children without giving them nightmares? And how can we provide an environmental education that teaches children that nature and people are inextricably linked?
You could start with One Planet Future, a short film produced by Green.TV and WWF, in which drawings and narration by schoolchildren are brought together by sound and animation experts (bit.lyOnePlanetFuture). It explores the "crazy business" of how rapidly we are devouring the world's resources.
Brightly coloured elephants, monkeys and tigers dance across the screen, while youthful voices tell us that there was once a time "when the world was innocent", when animals of every kind roamed freely. But then darkness fell over the Earth. Animals were hunted; the planet was transformed and polluted by roads and humans.
The film inspires children because it is made by children. It asks them to consider what could be done to improve the way we use natural resources. WWF and Green.TV believe that it is a useful first step towards helping a generation to realise the damage we are doing to our planet and to think about ways to change.
Ask your students to come up with ways to teach people how all living things are connected and are dependent on each other for survival.